Metal ductwork is used in many commercial and residential structures for moving or distributing air in the course of heating, ventilating, and air conditioning. Sheet metal sections are connected together either at a factory or at a construction site. Such ductwork most often has a rectilinear (square or rectangular) or circular cross sectional shape. Often, a main run has at least one branch extending along a major axis and connected to sections at angles thereto.
Clinch collar tabs extend along an edge so that they can be bent or crimped to a component (e.g., another branch, an elbow connection, or other fitting) so that the components interconnect to form a completed duct. The clips of a component are squeezed, hammered, or otherwise forced to bend them relative to their related component.
The corner joints, called Pittsburgh joints or locks, sometimes must be disassembled for purposes of removal or replacement. Also, when assembling the sheet metal ductwork, a common, longitudinal seam must be slightly opened while assembling the joint. This seam can be difficult and inconvenient to open; conventional tools are often not sufficient. The time consuming process can diminish productivity and increase costs. A more efficient method is needed.